Formatting your SD card ensures that it is made to efficiently store and operate within the Parkmate device. There are limitless devices that require SD cards in the world, each with their own requirements, so SD card is not only required to be formatted for each of them but will need their data wiped every time a format occurs to ensure quality operations. 

If you ever find that your Parkmate device is underperforming, or low on storage, it could be worth saving any files you deem valuable, then formatting your SD card.